Prepare rice according to package directions; keep warm.
Cut beef steak lengthwise in half, then crosswise into 1/8 to 1/4-inch thick uniform strips.
Combine vegetables and 3 Tbsp. water in large non-stick skillet. Cover and cook over medium-high heat 4 minutes or until crisp-tender. Remove and drain.
Heat same pan over medium-high heat until hot. Add half of beef and half of garlic; stir-fry 1 to 2 minutes or until outside surface of beef is no longer pink. Remove. Repeat with remaining beef and garlic.
Return all beef and vegetables to pan. Add stir-fry sauce and red pepper; heat through.
Spoon over rice. Sprinkle with peanuts, if desired.